Fals drum with a variable area vacuum-surface

ABSTRACT

A false drum servers used in the manufacture of tires having a hollow cylindrical drum with a perforated surface on the drum through which air is drawn. The drawn air creating a suction surface for holding flat or sheet materials that are to be cut before transferring onto a tire building drum. When smaller pieces of flat materials are being held on the drum, the perforations that are not covered allow air to flow freely into the drum, thereby reducing the suction adhering effect of the perforated surface. The present invention provides methods and apparatus for varying the amount of perforated area through which air can be drawn into the drum, thereby changing the amount of suction adhering surface area of the perforated drum.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a Divisional application of U.S. application Ser. No.09/952,635 having a filing date of Sep. 14, 2001 and a common assigneewith the present application.

[0002] This application relates to U.S. patent application Ser. No.09/952,536 (Publication No. US-2003-0051793-Al Published Mar. 20, 2003)having a filing date of Sep. 14, 2001 and a common assignee with thepresent application.

TECHNICAL FIELD OF THE INVENTION

[0003] The invention relates to methods and apparatus used in thepreparation of materials to be used in the fabrication of pneumatictires. In particular the invention relates to the perforated cylindricaldrum portion of a “False Drum” server on which elastomeric sheetmaterials are held while being cut prior to being transferred to a tirebuilding drum.

BACKGROUND OF THE INVENTION

[0004] It is known that in making vehicle tires, for example forautomobiles, that manufacture of a so-called carcass is first achievedby successively assembling several different components. In other words,the different carcass types included in a production range can bedistinguished from one another depending on the presence thereon of thevarious accessory components and/or the typology of the accessorycomponents themselves. By way of example, when carcasses for tubelesstires are to be produced, that is tires that in use do not require thepresence of an inner tube, the main components can be considered toinclude a so-called inner liner that is a layer of elastomericair-impervious material, a carcass ply, a pair of annular metalelements, commonly referred to as bead cores, around which the oppositeends of the carcass ply are folded, as well as a pair of sidewalls madeof elastomeric material, extending over the carcass ply at laterallyopposite positions. The accessory components may in turn comprise of oneor more additional carcass plies, one or more reinforcing bands foroverlying the carcass ply or plies at the areas turned up around thebead cores (chafer strips), and others.

[0005] Certain tire building assembly lines use servers of various kindsfor the purpose of securely holding flat materials such as tireinnerliner while it is being cut to size. Servers are commonly of theflat conveyor type, such as the one shown in British Patent No.1,010,597 (Dunlop Rubber Company) or the conveyor and cutting systemshown in U.S. Pat. No. 4,722,255 (Choate, et al.), wherein a continuousflat sheet of material is delivered upon a flat conveyor to a cuttingknife and then the material is removed to be placed upon the tire beingbuilt. Another such conveyor system is taught in U.S. Pat. No. 5,820,726(Yoshida, et al.), incorporating a “transfer drum” element which feedsmaterial to the conveyor system.

[0006] Drum servers, or so called “False Drum” servers, are analternative conveyor of flat or sheet tire materials that must be heldsecurely while being cut. After being cut, the sheet material is movedto the tire under construction on the building drum. Generally such aFalse Drum server consists of a horizontally disposed drum or cylinderthat is able to rotate about its cylindrical axis. One particular FalseDrum type server consists of a circular cylindrical drum that is hollow.The surface of the drum is perforated around most of its circumference,and air is pumped out of the drum in sufficient volume that the lowpressure within the drum provides a suction adhering surface which cansecurely hold the flat or sheet materials that are being cut while beingheld on the server. When a flat sheet of material, such as tireinnerliner, is placed on the perforated cylindrical part of the server,the pressure differential between the inside of the drum and the outsidecauses the flat material to adhere to the drum surface while thematerial undergoes a cutting operation.

[0007] An alternative drum-type server system which also holds flatmaterials to its cylindrical surface is taught in U.S. Pat. No.4,504,337 (Askam, et al.) which describes a drum type server systemwherein the method by which the flat materials that are held to be cutare held securely by a magnetic surface. Such a system, however, is ofcourse limited in use to flat or sheet fire materials that contain steelor ferromagnetic elements such as wires, cords or metal cloth.

[0008] The type of False Drum server described hereinabove, in which airis drawn through a perforated cylindrical surface as a method by whichto hold securely the materials being cut, is suitable for use withnonmagnetic sheet of flat material. Also suitable is the vacuum cupmethod taught in U.S. Pat. No. 4,891,082 (Broyles and Portalupi) wherein“sets of vacuum cups spaced circumferentially” around the circumferenceof the outer rim of a “transfer roll” which serves essentially the samepurpose as the aforementioned False Drum server. The vacuum cups arepumped individually by compressed air motors.

[0009] The suction adhering part of the perforated drum type False Drumserver is its perforated cylindrical drum surface. The False Drum serverhas a substantially bigger diameter than the building drum. Sheet rubbercomponents are measured to a required length on the False Drum server,and then are cut before being transferred to the building drum. Theelastomeric sheet or flat materials that are placed on the False Drumserver are held to the False Drum server because the pressuredifferential across the perforated cylindrical surface makes thecylindrical surface into a suction adhering surface.

[0010] False Drum servers generally have the advantage being faster thantraditional conveyor or belt type (flat) servers or roller conveyors interms of allowing greater speed of cutting of flat sheet materials. Adisadvantage of False Drum servers, however, is that for flatcomponents, such as innerliner and ply, the portion of the perforatedcylindrical surface that is not covered by the flat material being cutis open to the free flow of air into the drum. Such free flow of airweakens the pressure differential that holds the sheet material to thedrum. (Uncovered holes represent “leaks”.) One way to deal with thisleakage problem is simply to use adhesive tape or other materials toblock the flow of air through those portions of the perforated surfacethat are not covered by the flat sheet material. (In other words—plugthe holes.) But since the various pieces of material being cut are oftenof different sizes from one another, as typically happens when changingfrom a large tire component to a smaller component, the tape or otherair flow blocking material must be removed and replaced so that the lowpressure inside the drum can thereby be maintained. (You don't wantholes to be plugged where you want the vacuum-suction to hold material.)However, the time required to place tape over the unused portions of theperforated surface area, and remove it later, is undesirable. Anotherrisk of the tape hole-plugging method is contamination of the tirecomponents with pieces of adhesive tape that might work loose and attachthemselves to the sticky uncured elastomeric material.

[0011] An alternative to the use of tape is to use a massivelyover-dimensioned air pump to remove air from inside the False Drum. Witha sufficiently high capacity air (vacuum) pump, holes (leaks) become anon-problem. However, oversized pumps are not desirable because ofenergy consumption and environmental considerations as well as overallcapital costs and operating costs. Another solution is proposed in theaforementioned U.S. Pat. No. 4,891,082 (Broyles and Portalupi) whichdiscloses the use of individually controllable vacuum pumps for eachvacuum cup used to hold sheet materials on a cylindrical surface. Thismethod requires, however, that complex controls be used to control theindividual vacuum pumps to achieve both economy of operation and theability to provide a suction adhering surface having a size that rapidlyaccommodates flat sheets having different amounts of surface area ofspecific flat sheet materials being held by suction forces to thecylindrical surface.

[0012] What is needed is a technique for controlling the vacuum to theholes in the surface of a False Drum server, without requiring oversizedpumps and/or without requiring a plurality of pumps.

SUMMARY OF THE INVENTION

[0013] It is an object of the present invention to provide methods andapparatus as defined in one or more of the appended claims and, as such,having the capability of accomplishing one or more of the followingsubsidiary objects.

[0014] According to the invention, method and apparatus are provided forcontrolling airflow (suction) through (pressure differential across) aplurality of holes (perforations) extending through the outer surface ofa cylindrical drum.

[0015] According to a one aspect of the invention, two axially movabledisc-like baffle plates are provided within the drum, defining a volumetherebetween. The baffle plates are axially moveable, and sealinglyengage the inner surface of the drum. Their positions determine theeffective width (along the axis) of an area of the surface of the drumwhich will exert suction on a sheet of material laid on the surface ofthe drum.

[0016] According to another aspect of the invention, a circumferentiallymoveable curved cylinder segment is provided, conforming to the innersurface of the perforated cylindrical drum, and by circumferentiallypositioning the curved cylinder segment adjacent a portion of the innersurface of the hollow perforated cylindrical drum, the amount ofperforated surface area through which air can be drawn into the hollowcylindrical drum can further be controlled.

[0017] In this manner, suction can be provided only at selected ones ofthe perforations which correspond to a desired amount of surface area tobe used for holding elastomeric sheet materials on the outer surface ofthe drum.

[0018] An advantage of the present invention is that it providessimplified methods and apparatus by which to control or vary, on thehollow perforated cylindrical drum portion of a False Drum server, theportion of the total perforated surface area through which air can bedrawn into the cylindrical drum portion of the False Drum when theentire perforated area is not covered by sheet material being processed.

[0019] Another advantage of the present invention is to providesimplified methods and apparatus by which to control or vary, on theperforated drum portion of the False Drum server, the circumferentialdimension of the perforated area through which air can be drawn into theperforated drum.

[0020] Another advantage of the present invention is to providesimplified methods and apparatus by which to control or vary, on theperforated drum portion of the False Drum server, the axial dimension ofthe perforated area through which air can be drawn into the perforateddrum.

[0021] Another advantage of the present invention is to providesimplified methods and apparatus by which to move and otherwise positionfrom outside of the drum various airflow blocking devices placed insidethe hollow cylindrical drum.

[0022] Other objects, features and advantages of the invention willbecome apparent in light of the following description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Reference will be made in detail to preferred embodiments of theinvention, examples of which are illustrated in the accompanying drawingfigures. The figures are intended to be illustrative, not limiting.Although the invention is generally described in the context of thesepreferred embodiments, it should be understood that it is not intendedto limit the spirit and scope of the invention to these particularembodiments.

[0024] Certain elements in selected ones of the drawings may beillustrated not-to-scale, for illustrative clarity. The cross-sectionalviews, if any, presented herein may be in the form of “slices”, or“near-sighted” cross-sectional views, omitting certain background lineswhich would otherwise be visible in a true cross-sectional view, forillustrative clarity.

[0025] The structure, operation, and advantages of the present preferredembodiment of the invention will become further apparent uponconsideration of the following description taken in conjunction with theaccompanying drawings, wherein:

[0026]FIG. 1A is a schematic oblique view of a perforated cylindricaldrum;

[0027]FIG. 1B is a view of the drum of FIG. 1A with a sheet of flatmaterial being held to its perforated surface;

[0028]FIG. 2 is a schematic oblique view of a hollow perforatedcylindrical drum showing the regions of the perforated surface that areblocked or unblocked to airflow;

[0029]FIG. 3 is an oblique view of the hollow perforated cylindricaldrum with the knife guide removed to reveal the axially moveablecircular plates;

[0030]FIG. 4 is an oblique view of the hollow perforated cylindricaldrum with the knife guide in place but with the one endplate removed toreveal the axially moveable circular plates and the circumferentiallymoving semi-cylindrical plate; and

[0031]FIG. 5 is an oblique view of the semi-cylindrical plate and itssupport structure that fit inside the perforated drum.

DETAILED DESCRIPTION OF THE INVENTION

[0032] A False Drum server consists primarily of a hollow perforatedcylinder (drum) having a diameter substantially bigger than that of atire building drum. The drum is rotatable about its axis. Thecylindrical part of the drum is perforated (has holes) over between 50%and 80% and preferably about 66% of its cylindrical surface and the endsof the drum are sealed against airflow except as the flow of air frominside of the drum is provided by way of an air pump that removes airfrom the drum. Air moves into the drum through the perforated surface,because of the internally reduced pressure relative to the outside airpressure. The terms “drum” and “measuring drum” and “False Drum” serverare herein to be regarded as synonymous except as the term “drum” isspecifically referred to as an element or component of a False Drumserver.

[0033]FIG. 1A is an oblique schematic view of the perforated portion 104of the cylindrical drum 102 of the False Drum server 100. A portion 104of the overall cylindrical drum 102 is perforated. It has holes leadingfrom the exterior of the drum to the interior thereof. The portion 104is generally shaped like a rectangle wrapped around about ⅔ of thecircumference of the cylindrical drum 102. The perforated area is sizedaccording to the largest tires expected to be built on the machine. Theperforated portion 104 is, in its own right, a cylinder concentric withthe cylindrical drum 102, but having a lesser height than thecylindrical drum 102, and extending only partially around the surface ofthe cylindrical drum 102. Also shown in FIG. 1A is the axis 106 of thecylindrical drum 102 and one endplate 110 which covers and seals an endof the cylinder. The other end of the cylindrical drum 102 is alsosealed with an endplate (not visible in this view) so as to maintain alow pressure zone inside the cylinder; that is, both ends of thecylindrical drum are sealed in an airtight way. The cylindrical drum 102may rotate about the axis 106.

[0034]FIG. 1A further shows a region 108 which is not perforated and hasan arc width W subtending an angle a with respect to the axis 106. Thiscylindrical segment portion of the False Drum server houses a removableknife guide plate.

[0035] During use of the False Drum server, lengths of flat elastomericor other sheet materials such as tire innerliner can be placed (fed)onto and held onto the drum while being cut. After each given sheet ofmaterial is cut to size, it is transferred to the tire building drum(not shown). FIG. 1B shows the drum 102 of FIG. 1A with a piece of flatmaterial 119 being held on the surface thereof, by a pressuredifferential between the inside of the cylinder 102 and the outside.

[0036] Those skilled in the art will be aware that the efficiency ofsuch an arrangement in providing a suction adhering perforated surfaceby which to hold the flat material 119 securely could be improved if theportion of the perforated surface 104 that is not covered by the flatmaterial 119 is somehow otherwise covered in order to block the flow ofair into the drum 102. Unwanted air flow (leaks) will have the undesiredeffect of reducing the pressure differential that allows the sheetmaterial 119 to be held securely in place during the cutting operation.Typically, in standard operational practice, the portion of theperforated surface 104 which is not covered by material being held tothe surface is taped with masking tape or other suitable tape (notshown) to block the undesired flow of air into the drum 102 through theuncovered holes.

[0037] The present invention facilitates controlling the effectivedimensions of the perimeter areas of the perforated surface. That is,the present invention varies the effective area of the perforatedsurface in a controlled way along its edges, so that when smaller piecesof sheet material 119 are placed on the server, holes outside the areaof the material do not represent “leaks”. Time can thus be saved by nothaving to cover those portions of the perforated surface through whichair would otherwise be free to flow because they are not covered by thesheet material 119. In other words, the present invention providesmethods and apparatus by which to rapidly adjust the size of thatportion of the perforated area through which air can be drawn into thedrum 102.

[0038] While the apparatus described in U.S. Pat. No. 4,891,082 (Broylesand Portalupi) for providing a suction adhering surface of variable sizeincludes a variable area suction surface, it requires multiple pumps.The present invention has the benefit of using a single air pump toprovide a suction adhering surface area which is thereby simpler inconstruction. Moreover, the present invention maintains the existingapparatus and method of providing a uniformly cylindrically flatsurface. Also, it should be noted that the present invention is not perse a type of suction adhering surface, but rather is apparatus andmethods by which to vary, in a controllable way, the portion or area ofa perforated suction adhering surface that provides suction adherencefor individual flat sheet materials having differing dimensions from oneanother. In a sense, the present invention could be used with anexisting (prior art) drum surface, without modifying the surface per se.

[0039] The present invention includes two principal apparatuscomponents. One of them works to vary or limit, in a controllable way,the movement of air into the drum by way of the lateral (axial) regionsof the perforated area that are not covered by the sheet material 119being held in place. The lateral regions or areas are here defined asthe two separated portions of the perforated area 104 that are closestto the two endplates 110 of the cylindrical drum 102. In FIG. 1B the tworegions of the perforated area 104 that lie on either side of the sheetmaterial 119 are called herein lateral regions. The second componentworks to vary or limit, in a controllable way, the movement of air intothe drum by way of the semi-cylindrical regions or areas of theperforated area that are not covered by the sheet material being held inplace. In general, the semi-cylindrical regions or areas are definedherein as portions or areas of the perforated area 104 that extend atleast part way around the cylindrical drum. For example, in FIG. 1A, theperforated area contained within the area bounded by the letters A,B,Cand D is defined here as a semi-cylindrical area because it is curved inthe shape of a cylindrical segment which extends part way around theperforated portion 104 of the cylindrical surface 102.

[0040]FIG. 2 is an oblique schematic view of the False Drum 102 showingthe effect of the above-described two components on the size of theportion of the perforated area through which suction adhering force canbe applied to a piece of sheet material 119. The two lateral perforatedareas 114 a,114 b are the lateral portions of the total perforated area104 through which air cannot flow because of the presence of twocircular barriers 112 a,112 b, to be described in detail below, insideof the drum 102. The circular barriers 1112 a,112 b are essentiallydiscs, or baffle plates, which can be moved to different positionswithin the drum so that there is only vacuum in the space between thetwo axially-separated discs. The circular plates 112 a,112 b have aradius of curvature (r_(e)) less than the radius of curvature (r_(i)) ofthe inner surface 107 of the perforated cylindrical drum.

[0041] The two-headed arrows 113 show the directions of movement of thetwo circular barriers (baffle plates) 112 a,112 b, and of thecorresponding perforated lateral areas 114 a,114 b through which aircannot be drawn into the drum 102 due to the presence of the barriers.Also in FIG. 2 is shown semi-circumferential perforated region 123 whichis blocked to airflow by the presence of plate 120, to be described indetail below, also disposed inside of the False Drum 102.

[0042]FIG. 3 is an oblique view of a False Drum Server 100 comprising anouter cylindrical drum 102 with perforations 103 over the perforatedportion 104 of its surface. Inside the drum 102 are two circularbarriers 112 a,112 b (baffle plates) that are adjustable in relation toone another along the axis 106 of the drum. The circular barriers 112a,112 b are moveable in a symmetric way, i.e., towards or away from oneanother. The relative motions of the barriers (baffle plates) iscontrolled by a left-right handed screw (not shown) from the outside ofthe False Drum Server 100. The perimeter of each of the baffle plates112 a,112 b has a seal (not shown) such that each moveable baffle plateshas a substantially air-tight seal against the inside surface of theperforated cylinder 102, and so that the baffle plates can move axiallywithin the cylinder 102 with low friction during axial movement. Themovement of the baffle plates 112 a,112 b is preferably in equal butopposite directions, i.e., toward or away from one another, whichprovides a symmetric way to block the flow of air inside the drum 102from the lateral regions or areas 114 a,114 b of the total perforatedsurface region 104 of the cylindrical drum 102. This presumes that thematerial holding area on the exterior of the drum is desirablysymmetrical. If not, the baffle plates can certainly be individually andasymmetrically controlled with an appropriate mechanism.

[0043] Air is drawn from the cylindrical volume V between the two baffleplates 112 a,112 b. The air that is pumped from the volume V is removedby way of a pump and other apparatus (not shown) which communicate withthe innermost regions of the drum and the volume V such as by way of ahollow axle that is concentric with and internal to shaft 109 mounted inpillow blocks 105. Air pressure differential across the perforatedsurface in the region of the cylindrical volume V contained between thetwo baffle plates 112 a,112 b thereby allows the creation of a suctionadhering surface the lateral regions of which are adjustable. Note inFIG. 3 the open space 111 in the circumference of the cylindrical drumsurface 102. FIG. 4 shows that space 111 in FIG. 3 with a cylindricalsegment 116 having a cutting knife guide 117 installed. Since there isonly one volume V, there need only be one pump for removing air from thevolume and creating the desired pressure differential between the volumeV within the cylinder and the outer surface of the cylinder.

[0044] By adjusting the axial position of the barriers 112 a,112 binside of the drum 102, the width of the portion of the False Drumperforated surface 104 through which the air can be drawn can be variedto suit (e.g., match) the width required for a particular sheetcomponent being held to the drum. That is, the width dimensions of theportion of the perforated surface 104 that is able to provide a suctionadhering surface for sheet materials 119 is able to be varied accordingto the axial positioning of the internal baffle plates 112 a,112 b.

[0045] In other words, two axially slidable, baffle plates 112 a,112 bare placed within the interior of the drum 102. The outer diameter ofthe baffle plates 112 a,112 b is substantially equal to the innerdiameter of the drum 102. The space between the baffle plates 112 a,112b defines a chamber—in this case, a vacuum chamber. The baffle plates112 a,112 b may be positioned along the axis 106 of the hollowcylindrical drum 102 to vary the axial extent of the vacuum chamber, andthereby control the amount of perforated surface area through which aircan be drawn into the hollow cylindrical drum. Each of theaxially-moveable baffle plates 112 a,112 b is slidably sealed againstthe inner surface 107 of the perforated hollow cylindrical drum 102. Amechanism is provide for moving the baffle plates toward or away fromone another. For example, the baffle plates 1112 a,112 b each have aperimeter seal made of felt or other suitable material to block themovement of air around the perimeter of each of the two moveablecircular barriers or plates. The axially moveable baffle plates 112a,112 b disposed inside each opposing end of the perforated hollowcylindrical drum 102 are able to be moved towards or away from eachother to vary the width of a central perforated surface area throughwhich air can be drawn to provide an outer suction adhering surface 104on the perforated hollow cylindrical drum.

[0046]FIG. 4 shows essentially the same view of the False Drum server100 as is shown in FIG. 3, but with the endplate 110 removed and thecylindrical segment 116, with knife guide 117 secured in place. Alsoshown the FIG. 4 is an apparatus 121 comprised of a metal plate 120having the shape of a cylindrical segment and a central shaft 122 whichis connected to the plate 120 by way of the struts 124.

[0047] The apparatus 121 is shown independently, and outside of(separately from) the drum 102, in FIG. 5. The apparatus 121 consists ofa metal plate 120 having the shape of a cylindrical segment having aradius of curvature R about the central shaft 122. The radius ofcurvature R is slightly less than the radius of curvature of the insideof the perforated drum 102. The plate 120 is attached to the centralshaft 122 by struts 124. The overall length of the portion of theapparatus 121 between the most separated portions of the support struts124 is less than the length of the cylindrical drum 102.

[0048]FIG. 4 shows the apparatus 121 installed inside the drum 102having the perforated surface area 104 with perforations 103. FIG. 4also shows one of the barrier plate 112 a inside the drum 102. Note thatthe circular barrier plate 112 a (and also the barrier plate 112 b,which is not shown) is designed to move axially along axis 106 insidethe drum 102. The aforementioned seals extending outward from theperimeter on each of the two barrier plates 112 a,112 b can seal againstunacceptable levels of airflow between the perimeters of the barrierplates 112 a,112 b and the inner surface 107 of the cylindrical drum 102in the perforated region 104. The perimeter seals of the two barrierplates 112 a,112 b are also able to ride over the thin metal plate 120of the apparatus 121.

[0049]FIG. 5 is an oblique view of the semi-cylindrical plate supportand moving apparatus 121 that is discussed hereinabove which is, likethe two axially moving circular barriers 112 a,112 b, disposedinternally of the False Drum 102. A metal plate 120 has the shape of acylindrical segment having a radius of curvature R from axis 106 throughthe central shaft 122, which is slightly less than the radius ofcurvature of the inner surface 107 of the perforated drum 102. The plate120 is attached to the central shaft 122 by struts 124. The overalllength L of the portion of the apparatus 121 between the most separatedportions of the support struts 124 is less than the length of theinterior of the drum 102.

[0050] When the plate 120 is disposed inside of the drum 102, and theplate 120 is adjacent the inner side of the perforated portion 104 ofthe drum 102, the movement of air into the drum from the outside isthereby impeded in that region. That is, the plate 120 blocks the flowof air into the drum 102 through the portion of the perforated area thatis covered by the plate which is made of rigid, thin sheet material.

[0051] It is important to note that the plate 120 is made of thin, rigidmaterial in order to withstand the pressure differential between theinside of the drum 102 and the outside of the drum without deflectinginward toward the center of the drum. Those who are knowledgeable of thearts of mechanical design will note that the cylindrical segmental shapeof the plate 120 will contribute to the rigidity of the thin metal platein withstanding the pressure differential.

[0052] Referring to FIG. 5, there is shown provided a mechanism 126 bywhich a hand crank 128 or a motor-controlled shaft can convey to theapparatus 121 supporting the plate 120 an angular motion and a fixedangular position inside of the drum 102.

[0053] It is within the scope of the invention that both controlling thelateral and semi-cylindrical size of the openings 103 into False Drum102 limit, control or vary the dimensions of that portion of theperforated surface area 104 of the perforated drum 102 through which aircan be drawn into the drum. The two circular barriers (baffle plates)112 a,112 b (FIGS. 3 and 4) are intended to move axially within theregion between the support struts 124 of the plate 120. The thinness ofthe plate 120 is such that the perimeter seals on the barrier plates 112a,112 b will accommodate the plate, sealing adequately against theunwanted flow of air around the perimeters of the barriers in theimmediate region where the perimeter seals meet, ride over, and slideupon the plate 120.

[0054] The circumferentially moveable, cylindrically curved plate orelement 120 disposed inside the hollow cylindrical drum 102 has an axisof rotation contiguous with the axis of the hollow cylindrical drum andhas a length less than the length of the cylindrical volume inside thehollow cylindrical drum, and an outermost radius of curvature aboutequal to the radius of curvature of the inner surface 107 of the hollowperforated cylindrical drum. The circumferentially moveablecylindrically curved element 120 has an arc width in the range of about60 degrees to about 120 degrees, and preferably about 80 degrees to 90degrees with respect to the axis of rotation of the cylindrically curvedelement.

[0055] In other words, a circumferentially moveable curved cylindersegment conforming to the inner surface 107 of the perforatedcylindrical drum is located inside of the hollow drum. The amount ofperforated surface area through which air can be drawn into the hollowcylindrical drum is varied by circumferentially positioning the curvedcylinder segment adjacent a portion of the inner surface 107 of thehollow perforated cylindrical drum.

[0056] It may be useful to envision the perforated area as being (asmentioned above), essentially a rectangle wrapped around about 50% to80% and preferably about 60% to 70% of the circumference of the cylinder102. The perforated area is sized according to the largest tiresexpected to be built on the machine. The rectangle has a length thatextends part way circumferentially around the cylinder and a width thatextends across most of the axial length of the horizontally disposedcylindrical drum or False Drum server. The operation of the inventionreduces or increases the “effective” width and/or length of theperforated rectangular area according to the sizes of the pieces of flatsheet material desired to be held on the surface of the False Drumserver required for the size of the tire being manufactured, during themeasuring out of the material, the cutting to length and holding thematerial till its assembly into the tire.

[0057] Although the invention has been illustrated and described indetail in the drawings and foregoing description, the same is to beconsidered as illustrative and not restrictive in character—it beingunderstood that only preferred embodiments have been shown anddescribed, and that all changes and modifications that come within thespirit of the invention are desired to be protected. Undoubtedly, manyother “variations” on the “themes” set forth hereinabove will occur toone having ordinary skill in the art to which the present invention mostnearly pertains, and such variations are intended to be within the scopeof the invention, as disclosed herein.

What is claimed is:
 1. A method for controlling the amount of perforatedsurface area on a perforated cylindrical outer surface of a hollowcylindrical drum, through which air can be drawn into the hollowcylindrical drum having an inner surface, to provide a suction adheringsurface for holding sheet materials on the outer surface of the drum,the cylindrical drum having a diameter and an axis, and the methodcharacterized by the steps of: providing two axially movable disc-likebaffle plates within the drum, each having a diameter substantiallyequal to the diameter of the drum; and varying the axial positions ofthe baffle plates to control a portion of the perforated surface areathrough which air can be drawn into the hollow cylindrical drum.
 2. Themethod of claim 1, further characterized by the step of: slidablysealing each of the baffle plates against the inner surface of the drum.3. The method of claim 1, further characterized by the step of: movingthe baffle plates toward or away from one another.
 4. The method ofclaim 1, further characterized by the step of: moving the baffle platestoward or away from one another with axial symmetry.
 5. The method ofclaim 1, further characterized by the step of: removing air from avolume of the interior of the drum between the two baffle plates.
 6. Amethod for controlling the amount of perforated surface area on aperforated cylindrical outer surface of a hollow cylindrical drum havingan inner surface, through which air can be drawn into the hollowcylindrical drum to provide a suction adhering surface for holdingelastomeric sheet materials on the outer surface of the drum, the methodcharacterized by the steps of: providing, within the drum, acircumferentially moveable curved cylinder element conforming to theinner surface of the perforated cylindrical drum; and controlling theamount of perforated surface area through which air can be drawn intothe hollow cylindrical drum by circumferentially positioning the curvedcylinder segment adjacent a portion of the inner surface of the hollowperforated cylindrical drum.
 7. The method of claim 6, furthercharacterized by the step of: providing two axially movable disc-likebaffle plates within the drum, each having a diameter substantiallyequal to the diameter of the drum; and varying the axial positions ofthe baffle plates to control a portion of the surface area through whichair can be drawn into the hollow cylindrical drum.
 8. Apparatus forcontrolling suction through perforations extending through a surface ofa hollow cylindrical drum having an inner surface, a circumference and aaxis, characterized by: a circumferentially moveable cylindricallycurved element disposed inside the hollow cylindrical drum and having anaxis of rotation contiguous with the axis of the hollow cylindrical drumand having a length less than a length of a cylindrical volume insidethe hollow cylindrical drum, and an outermost radius of curvature aboutequal to a radius of curvature of the inner surface of the hollowperforated cylindrical drum; and axially moveable baffle plates disposedinside the drum, each baffle plate having a radius of curvature lessthan the radius of curvature of the inner surface of the perforatedcylindrical drum.
 9. The apparatus of claim 8 characterized in that thecircumferentially moveable cylindrically curved element has an arc widthin the range of about 60 degrees to about 120 degrees with respect tothe axis of rotation of the cylindrically curved element.
 10. Theapparatus of claim 9 characterized in that the circumferentiallymoveable cylindrically curved element has an arc width in the range ofabout 90 degrees with respect to the axis of rotation of thecylindrically curved element.
 11. The apparatus of claim 9 characterizedin that each of the axially moveable circular barriers disposed insideeach opposing end of the perforated cylindrical drum has a perimeterseal made of felt or other suitable material to block the movement ofair around the perimeter of each of the two moveable circular barriers.12. The apparatus of claim 9 characterized in that: each of the axiallymoveable circular barriers disposed inside each opposing end of theperforated hollow cylindrical drum are able to be moved towards or awayfrom each other to vary the width of a central perforated surface areathrough which air can be drawn to provide an outer suction adheringsurface on the perforated hollow cylindrical drum. moving the baffleplates toward or away from one another.
 4. (Cancelled) The method ofclaim 1, further characterized by the step of: moving the baffle platestoward or away from one another with axial symmetry.
 5. (Cancelled) Themethod of claim 1, further characterized by the step of: removing airfrom a volume of the interior of the drum between the two baffle plates.6. (Cancelled) A method for controlling the amount of perforated surfacearea on a perforated cylindrical outer surface of a hollow cylindricaldrum having an inner surface, through which air can be drawn into thehollow cylindrical drum to provide a suction adhering surface forholding elastomeric sheet materials on the outer surface of the drum,the method characterized by the steps of: providing, within the drum, acircumferentially moveable curved cylinder element conforming to theinner surface of the perforated cylindrical drum; and controlling theamount of perforated surface area through which air can be drawn intothe hollow cylindrical drum by circumferentially positioning the curvedcylinder segment adjacent a portion of the inner surface of the hollowperforated cylindrical drum.
 7. (Cancelled) The method of claim 6,further characterized by the step of: providing two axially movabledisc-like baffle plates within the drum, each having a diametersubstantially equal to the diameter of the drum; and varying the axialpositions of the baffle plates to control a portion of the surface areathrough which air can be drawn into the hollow cylindrical drum. 8.(Currently amended) Apparatus for controlling suction throughperforations extending through a surface of a hollow cylindrical drumhaving an inner surface, the cylindrical drum being closed at oppositeends to prevent air flow into the drum through the opposite ends, acircumference and an axis of revolution, characterized by: acircumferentially moveable cylindrically curved element disposed insidethe hollow cylindrical drum and having an axis of rotation contiguouswith the axis of the hollow cylindrical drum and having a length lessthan a length of a cylindrical volume inside the hollow cylindricaldrum, the curved element conforming to the inner surface of theperforated cylinder drum and an outermost radius of curvature aboutequal to a radius of curvature of the inner surface of the hollowperforated cylindrical drum; and axially moveable baffle plates disposedinside the drum to control a portion of the perforated surface betweenthe baffle plates, each baffle plate having a radius of curvature